Planned maintenance is agreed as a cycle and then run as a series of individual visits. Each one gets booked when somebody remembers or when something breaks, so the cycle is only checked after the equipment has already failed. The notes are the second loss. A technician who writes that there is a slow loss on the low side and recommends a leak search has done the diagnostic work; if that sentence lives on an invoice rather than on the unit, the next person starts from nothing.
The air conditioning is not cooling properly. Asked when it was last serviced, the record answers fourteen months ago against a six month interval — two visits missed. The more useful part is the note left on that visit: slow loss on the low side, recommend a leak search next time. There was no next visit. The forecourt price sign opens the same way: the digits blank intermittently and worse in the cold, and its history already holds a reseated controller, a replaced driver and the annual structural inspection.
